In such a conventional ski binding part according to German OS No. 15 78 887, in which, however, no further sole or heel holder is provided, the lever arms engage a socalled stroke reducer. Same is a part onto which acts the spring and which is movable transversely with respect to the active direction of the spring, wherein inclined surfaces of the lever arms slide on inclined surfaces of the stroke reducer. This is not only a very expensive construction, but also a construction which is easily susceptible to breakdown. Furthermore, very high friction forces occur between the moveable stroke reducer, support with respect to the spring and the inclined surfaces of the toggle-lever arms.
In an improved embodiment these disadvantages were avoided by constructing the movable part in the form of a rack as a rotary member with at least one rotating groove and movably supporting same in the longitudinal center plane of the jaw between the pivot axes of the sole holders. One precaution was here also taken, namely, a further sole or heel holder is provided between the two sole or heel holders, which further sole or heel holder is pivotal about an axis which is arranged transversely with respect to the longitudinal center plane of the jaw and parallel with respect to the upper surface of the ski, grips over the sole of the shoe or the heel and also with at least one extension engages the groove which is arranged on the spring-loaded rotary member. All these embodiments are described in Austrian Patent No. 315 041.
One disadvantage of this known construction consists in the further sole or heel holder opening in the same degree as the two sole or heel holders, so that, even if no vertical forces occur, which would cause a release of the further sole or heel holder, same releases the sole or the heel of the ski boot and through this also brings about undesired release operations. It is particularly disadvantageous that the skier, in the case of forces which purely act in the horizontal plane, looses the hold of the ski shoe from above, which causes during downhill skiing an insecurity. Finally, a still further disadvantage of this known solution lies in all release operations being started against the force of one single spring, however, as is known, the release force which acts in the horizontal plane is to be approximately half the size of the force which acts in the vertical plane.
A different front jaw is described in German OS No. 20 44 264, in which, however, only the individual sole holders are provided, which can be released either against the force of one single spring or against the force of each one single spring.
German OS No. 19 06 364 describes a front part of a safety ski binding, in which a one-part sole holder can be swung against the force of a spring both in a horizontal and also in a vertical plane, wherein the swinging in both planes occurs so to speak according to a pregiven control. For this reason, this conventional construction is just as disadvantageous as is the solution according to Austrian Patent No. 315 041 with the further sole or heel holder, wherein an additional disadvantage consists in the single sole holder releasing during the release operation an area of the ski shoe, however, at the same time clamping the other area of the same, which can cause undesired frictions.
A different embodiment according to German OS No. 28 12 149 uses also a one-part sole holder, which can be released against the force of one single spring, wherein for the purpose of control in a vertical plane, additional intermediate pieces are provided, which assure a pivoting of the sole holder about a horizontal axis, as soon as forces acting in this direction occur. Again, the increased number of structural parts is disadvantageous in this known construction, which parts cause additional friction forces inside of the jaw member. The difference between the forces which act in the horizontal and in the vertical plane can thereby only be overcome by suitable translations of said additional structural parts, which circumstance results necessarily in compromising solutions.
The purpose of the invention is to provide design of a front or rear jaw of the abovementioned type so that the listed disadvantages are avoided and this jaw reacts both to a pure horizontal and also a pure vertical release and, in addition, also to a diagonal release having both vertical and horizontal components of movement due to its construction and through compensating the occuring friction forces.
The set purpose is inventively attained by the support member being also guided in longitudinal direction of the ski, and being pressed against the shoe by a further spring. This measure makes it possible for the support member which supports the two sole or heel holders to be moved in direction of the longitudinal axis of the ski at the occurrence of an overload, thus without friction of the ski shoe as easier release of the same can be assured. Also, in the case of a twisting fall which as is known is dangerous, the release of the ski shoe is made substantially easier.
A particularly advantageous embodiment of the invention consists in the down-holding means being able to be swung out against the force of the further spring. In this manner the spring forces and characteristics which are decisive for the horizontal and vertical release can be determined in an optimum manner, whereby the two springs are then together effective for the release operations.
According to the invention, it is further provided, that the first spring, which is effective against a lateral release, as it is known by itself, is constructed as a tension spring, however, the further spring is constructed as a pressure or compression spring, and that the two springs are preferably arranged concentrically to one another, wherein the compression spring envelopes the tension spring. Through this measure a concentric design of the jaw is assured.
A different inventive thought consists in the end of the tension spring, which end faces the support member, being anchored on a slide member which preferably also has an indicator, which slide member in turn can be adjusted together with the support member and relative with respect to the ski-fixed abutment. This measure creates a particularly simple connection for the tension spring on the slide member, which permits a loading of the two extensions of the individual sole or heel holders. Furthermore, an indicator can be provided directly on the slide member, through which the number of the necessary structural parts can be reduced.
In a further development of the thought of the invention, a slide member is provided which slides in the groove of a guide piece, to assure a swinging out of the individual bent levers independently from one another.
A different thought of the invention lies in a jaw, in which the two sole or heel holders are designed as bent or two arm levers, such that the support member is constructed as a frame supporting a guide plate which is movable on the rail of the jaw and on its upwardly projecting region a bearing sleeve, on which is provided by means of a bearing axle a support part for the further sole or heel holder, wherein the latter is held on the support part with an elastic element positioned therebetween. This measure assures, that, during a release operation in the vertical direction, the further sole or heel holder constantly maintains its vertical position, whereby the elastic element is slightly deformed between the support part and the sole down-holding means.
In a still further characteristic of the invention, there are provided two sliding surfaces in the region of the ski-fixed part which extend in a plane which lies substantially vertically with respect to the upper surface of the ski and normally with respect to the longitudinal axis of the ski, on each of which sliding surfaces rests a roller in the downhill skiing position, which rollers are supported on the lateral arms of a support part of the further sole or heel holder, that the two rollers are arranged resting on the sliding surfaces and are arranged slidably movably along the same, and that the two sliding surfaces each have a roll-off edge, which is exceeded by the rollers upon reaching a predetermined overload, whereby the further spring (compression spring) is at least at times relieved and the further sole or heel holder is released.
Through the listed inventively important measures, it is achieved in the end effect that with a simultaneous movement upwardly and toward the fixed part, the friction is compensated for and practically a constant release force is achieved, whereby the tension spring relaxes, however, the compression spring is loaded.